Gas-pressure control



Dec. 22, 1925. 1,566,279

. R W KING GAS PRESSURE CONTROL Filed Jan. l0, 1921 l/ll.

Affjf.

Patented 22, -f

UNITED `s-'r.11vrr.s

PATENT ori-lon ROBERT W. KING, Ol' NEW YORK, N.. Y., ASBIGNOR TO WESTERN ELECTRIC COMPANY,

a 4INcomoanrinzo, or NEW YORK, N. Y., A GQRPORATION F NEW YORK.

I GAS-PRESSURE CONTROL.

Application nled January '1.0, 1821. Serial No. 436,167.

- To all 'wliom z't may concern.'

j Be it known that I, ROBERT W. KING, a citizen of the United States, residing at New York, in the county of New York, State of New York, have invented certain new and useful Improvements in Gas-Pressure Controls, of which the following is a full, clear,

concise, and exact description;

v This invention relates `to the regulation of gas pressures and more articularly the regulatlon of pressure in e ectric discharge dev1ces.

An object of the invention is to so regu- A further object of the invention is to provide sensitive a paratus for maintaining an enclosedv bo y of gas at a substantially constant pressure.

In the preferred way of attaining these objects, use is made of the circuit and` electrode arrangement of an ionization manometer such as that disclosed in the patent to O. E. Buckley, No. 1,372,798, granted March 29, 1920. A device such.as a pump, or its equivalent,`may be employed continuously to withdraw as from the vessel or, if the discharge device is of a type which continuously absorbs gas, this may be omitted. Means for intermittently admitting gas into the vessel is provided and the admisv sion of gas is controlled by the ionization current of the manometer. Instead of admitting gas from the exterior of the vessel, a substance may be placed in the enclosed space which has the property of occluding gases under some conditions and of giving up the occluded gases under other conditions which may be controlled by -the ionization current.

The invention will be more fully understood from the following detailed description taken in connection with the accompanying drawings in which Fig. l represents diagrammatically an arrangement embodying the, invention, and Fig. 2 is a similar view showing a modification.

Referring to the drawings, by reference numerals, a vessel 10, shown in the drawing as an X-ray tube, in which it is desired to maintain a constant pressure, is connected b a passage 12 to the chamber 14. The c amber 14 is connected through a membrane 16 to a chamber 18 which may be connected-to anysuitable source of gas (not shown). The membrane 16 may be of some substance such as palladium which, when cooled, is impervious to gas but, when heat'- ed, will permit the flow of gas therethrough.

The chamber 14 is also connected through the narrow passage 20 vto a chamber 22 containing charcoal 24 or similar material, having the ability to absorb gas. As shown, chamber 22 may vbe surrounded by a liquid air containing vessel 26 for the cooling the charcoal. This device acts as a pump for continuously withdrawing gas from the chambers `14 and 10. It is, of course, obvious that any other suitable form 'of pumping' mechanism may be employed.

The chamber 14 contains a ilamentary cathode 28 heated by a battery 29, an anode 30, and a collector electrode 32. These are the usual electrodes ofan ionization manometer. Space current between the cathode 28 and anode 30 is supplied by the source of current 34. The electrode 32 is given a negative potential by battery 36, lower than electrodes 28 and 30 and as described in the Buckley patent, above referred to, acts as a collector for positive ions which may be produced in the adjacent space by the space current of negative electrons between cathode 28 and anode 30. The amount of ionization produced by a given space current is directly proportional to the pressure of the gas and the current in the branch of the circuit comprising electrode 32 is therefore porportional to the gas pressure.

A relay 38 is placed in the collector circuit and is adjusted to be actuated by the current therethrough when it has reached a given value. The relay 38 controls a circuit comprising a lilamentary heating element 40 which is heated by a battery 42. The heating element 40 may be used for heating the membrane 16 by direct radiation of heat. Preferably, however, filament 40 is formed, at least in part, of thermionically active material and 1s connected .to membrane 16 through a source fof current 44 which supplies a s ace current between elements 40 and 16 w en the former is heated. The circuit through battery 42 is normally closed as shown. As soon, however, as the4 pressure in the chamber 14 has reached the desired value, current through relay 38 is of suiiicient value to 'open-circuit battery 42 purpose of thus allowin the membrane 16 to cool and reventing t e further admission of gas. gince the current through relay 38 is directly proportional to the gas pressure, very sensitive means is thus provided for. maintaining the pressure constant within very narrow limits.

The sensitivity of the device may be increased by causing the collector current to flow across a resistance 46 in the input circuit of a vacuum tube amplifier `48 as shown in Fig. 2. A battery 52 may' be employed, if desired, to maintain the control electrode of ampliier 48 negative with respect to the cathode. The output current of amplifier 48 flows through a relay 54 which may control a device similar to that` controlled by relay 38 in Fig. 1, or as shown in Fig. 2, may control a somewhat similar arrangement which comprises a thermionic filament 56 within a chamber 58 and an anode wire 61 in conductive relation to a material 62. This material may be, for example, spongy platinum, charcoal, or potassium hydroxide which, when cooled, will absorb gas and when heated, will give it oil'. The battery 49 is so connected that when relay 54 is in its normal position, space current will iiow between the filamentary cathode 56 and the anode comprising elements 61 andl 62,the latter being heated by bombardment to emit gas. No means for withdrawing gas from the enclosed space is shown in Fig. 2, this being illustrative of the case where a device, such as an X-ray tube, has the characteristic of increasing its vacuum or becoming harder when being operated. v

Although only two types of devices for supplying gas have been illustrated, it is obvious that other devices having this function may be operated by changes in the ionization current, such, for example, as the valve shown in U. patent to Moore, No. 895,487, dated August 11, 1908.

While the ionization electrodes are shown in a chamber 14 somewhat distant from the main chamber 1() so as to be as far removed as possible from the ionizing currents of the main discharge, it is to be. understood that the invention is not limited to this arrangement but in certain cases the electrodes 28, 30 and 32 may be placed in the main vessel.

What is claimed is: l 1. The method of regulating the gas ressure in a device, which comprises ionizing a portion of the gas at a rate substantially proportional to the pressure, and supplying gas to said device at a rate controlled by said ionization.

2. The method of regulating the gas pressure in a device, which comprises ionizing a portion of the gas at a rate substantially proportional to the pressure, causing a current to vflow substantially proportional to said ionization, and supplying gas to said device in response to variations in said current.

3. The method of regulating the gas pressure in a device, which comprises ionizing a portion of the gas at a rate substantially proportional to the pressure, causing a current to flow substantially proportional to said ionization, amplifying variations in said current, and supplying gas to said dcvice in response to said ampliied variations.

4. The method of regulating the gas pressure in a device, which comprises continuously withdrawing gas from said device, producing ionization in said device, and supplying gas to said device at a rate controlled by said ionization.

5. The method of regulating the gas pressure in a device, which comprises continuously withdrawing gas from said device, producing ionization in said device, causing a current to How in response to said ionization, and supplying gas to said device at a rate controlled by variations in said y current.

6. The method of regulating the gas pressure in an electric discharge device, which comprises ionizing the gas at a point remote from the main discharge at a rate varying with pressure changes, and supplying gas to said device in response to changes in said ionization.

7. In combination, a chamber containing gas, means for varying the pressure of the gas in said chamber, means for producing ionization in said chamber in proportion to said pressure, and means for controlling said pressure varying means in response to said 1on1zat1on.

8. In combination, a chamber containing gas, means for varying the pressure of the gas in said chamber, means for producing a discharge of negative electrons through said gas, a circuit comprising an electrode for collecting positive ions produced by said electron discharge, and a relay operated by the current in said circuit for controlling said pressure varying means.

9. In combination with an electric discharge device having a main discharge chamber, a chamber connected thereto by a relatively narrow passage, means for producing ionization in said second chamber and means for controlling the pressure in said device in response to variations in said ionization.

l0. The method of regulating the gas pressure in an electric discharge device, which comprises ionizing the gas at a point remote from the main discharge at a rate varying with pressure changes, and changing the pressure in said device in response to changes in said ionization.

1l. In a gaseous discharge device having gamme y main discharge electrodes, means for ionizing the gas at a point remote from said main discharge electrodes, a substance containing occluded gas and means to establish an electron stream im inging on said substance, said means eing responsive to changes in ionizanion due to variations in gas pressure.

12. In combination, a gas filled container, means for varying the pressure therein, means for establishing an electronicspace current in said container an electrode adjacent'to said means and maintained at a potential more negatlve than any part of said means, and means responsive to current 15 ROBERT W. KING. 

